Reminded me striking on this post:
Belt twisted twice
Could you please check the condition of part 338?
Do you have a pic of your freewheel’s tooth?
Twisting occurs when the belt tension is low or slack.
The new U.S. distributor had me send the bike to them. They determined the bike was improperly assembled, and replaced all of the hardware for the rear wheel assembly. They also adjusted the bottom bracket after discovering the front pulley was moving in an odd manner.
I had noticed a sensation of rear wheel wobble when riding downhill, but could not see any play upon inspection. Turned out I wasn’t imagining things as the wheel had 3mm of play in it. I suspect the looseness allowed the belt to creep off the sprocket when under load.
I’ll report back after I’ve had a few days with it. The Strida is a fun bike to ride, but my experience has been greatly undermined by careless workmanship. I think the use of clear plastic washers, as well as other plastic, makes the bike seem more like a toy than a bicycle.
Was able to ride a few times, but something felt wrong. The rear wheel has some lateral movement and the left handlebar has the same wiggle issue as before. So, my bike is boxed up awaiting UPS pickup.
This is obviously a problem due to the lack of preload of the rear joint, see the full explanation here: [url]Sideway movement of the rear wheel - #29 by Blackstridaaustria]
BSA has developed some parts that solve the issue, please contact him.
@Bietrume
To be honest…I didn’t think of this issue by now, guess I was detracted by the improper assembling 
But indeed yes - you will be right…
@ImpairedVisions
If you - or your mechanic - also believe that the behaviour of your bike matches above mentioned issue you might actually think about trying our parts.
I’ve sent you already detailed info 
Thanks for the information! Recently, Ive wondered why there isn’t a “Performance Kit” to improve the Strida. There is an entire cottage industry supplying various upgrades for Brompton.
And there’s the European bike market which supports Brompton, but not Strida.
I’m sure behind Brompton and their friends are standing also advertising specialists.
Ming cycle’s budget for European advertising will be truly different to that of Brompton.
I believe the Strida is still too uncommon - in U.S. and Europe - to be of interest for bike dealers.
Moreover that are - as I sadly had to notice - several Strida dealers across the world highly interested to sell Strida, but not to take care of service or spare parts supply. 
Just a quick report: Bike has been riding better since getting it back, but today the belt became twisted again. The new US distributor seems to be at a loss. During previous belt twistings the disc rotor became warped. I wonder if there is a warped spot that is behaving like a deraler, and causing the belt to be slightly shifted over – resulting in these twisting events.
What did the US distributor to temporarily solve the issue? If he just changed the belt, then it will come back for sure.
I am convinced that your rear pulley gets misaligned (= not parallel to the front pulley) when you put effort on the pedals. The belt then climbs on the pulley flange and gets twisted.
As suggested in my previous post (see above), the preload of the rear joint has become too low, which causes this lateral movement of the rear wheel and consequently the belt twisting.
Several solutions exist: BlackStridaAustria will help you to choose the best one.
@Bietrume
You might be - exceptionally - wrong here…
Of course I’d love to help ImpairedVisions, but the problem seems to be that he can’t find a local mechanic
I don’t think so: There are a few mm’s between belt and and disc; usually you would feel a disc dent of a half mm while breaking.
If the disc would be that much bent to reach near the belt - then would your rear brake not be functional.
You wrote above “they replaced all the hardware” - do you have verified info what exactly they did?
I’d really like to know -
- was the freewheel replaced?
- what about part 338?
- did they renew the cup spring, washer and the rear axle bolt?
Freewheel was not replaced, but all other hardware was. I think I have a lemon, and asked for a new bike.